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1.
Mol Ecol ; 23(13): 3306-21, 2014 07.
Artigo em Inglês | MEDLINE | ID: mdl-24888550

RESUMO

Despite no obvious barriers to gene flow in the marine realm, environmental variation and ecological specializations can lead to genetic differentiation in highly mobile predators. Here, we investigated the genetic structure of the harbour porpoise over the entire species distribution range in western Palearctic waters. Combined analyses of 10 microsatellite loci and a 5085 base-pair portion of the mitochondrial genome revealed the existence of three ecotypes, equally divergent at the mitochondrial genome, distributed in the Black Sea (BS), the European continental shelf waters, and a previously overlooked ecotype in the upwelling zones of Iberia and Mauritania. Historical demographic inferences using approximate Bayesian computation (ABC) suggest that these ecotypes diverged during the last glacial maximum (c. 23-19 kilo-years ago, kyrbp). ABC supports the hypothesis that the BS and upwelling ecotypes share a more recent common ancestor (c. 14 kyrbp) than either does with the European continental shelf ecotype (c. 28 kyrbp), suggesting they probably descended from the extinct populations that once inhabited the Mediterranean during the glacial and post-glacial period. We showed that the two Atlantic ecotypes established a narrow admixture zone in the Bay of Biscay during the last millennium, with highly asymmetric gene flow. This study highlights the impacts that climate change may have on the distribution and speciation process in pelagic predators and shows that allopatric divergence can occur in these highly mobile species and be a source of genetic diversity.


Assuntos
Mudança Climática , Ecótipo , Variação Genética , Genética Populacional , Phocoena/genética , Animais , Oceano Atlântico , Teorema de Bayes , DNA Mitocondrial/genética , Fluxo Gênico , Genótipo , Mar Mediterrâneo , Repetições de Microssatélites , Modelos Genéticos , Phocoena/classificação , Densidade Demográfica , Dinâmica Populacional , Análise de Sequência de DNA
2.
Mar Pollut Bull ; 95(2): 658-64, 2015 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-25636829

RESUMO

Juvenile flounders (Platichthys flesus), collected in two estuaries with similar temperature regimes (the heavily polluted Seine and the moderately contaminated Vilaine), were submitted to a common garden experiment. After an acclimation period, both populations were challenged by a thermal stress (9-24°C for 15days, then maintenance at 24°C for 19days). The condition factor of the Vilaine fish increased in both conditions, while it decreased for the heated Seine flounders after 34days. The expression of genes related to the energetic metabolism was measured in the liver. The expression levels for ATP-F0 and COII were significantly reduced for heated vs. standard fish from both estuaries, while a decrease of the 12S expression was detected only in heated vs. standard fish from the Seine estuary. Thus, it is suggested that highly contaminated fish from Seine could display a lower tolerance to thermal stress, compared to moderately contaminated fish from Vilaine.


Assuntos
Monitoramento Ambiental , Linguado/fisiologia , Estresse Fisiológico , Temperatura , Poluentes da Água/toxicidade , Animais , Estuários , Linguado/metabolismo , Tolerância Imunológica , Fígado , Dinâmica Populacional
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